Within the broadcast industry, there exist Media Area Networks (MANs) that comprise a host system, in the form of a central processor that executes a non-real time operating system. A host bus adapter links the host system to a storage system that includes one or more storage devices. Each device can take the form of a stand-alone disk or a Redundant Array of Inexpensive Disks (RAID). In practice, each storage device holds digitized video accessible for editing and/or broadcast. To assure reliability, all components within the MAN are fault tolerant and have redundant features in an effort to offer real time recovery in the event of a fault. Such real time recovery becomes especially critical when the video stored in one or more of the storage devices of the storage system undergoes live transmission.
When a fault occurs in a MAN, the location of the fault can affect the time required for recovery. For example, consider a fault associated with a port assigned to a storage device. Upon the occurrence of such a fault, an error signal propagates into a fibre channel fabric that carries the error signal to the host bus adapter. The host bus adapter typically has the capability the switching between the failed port and an alternative port to recover from the fault. Unfortunately, present-day host bus adapters do not inherently support the real-time requirements of a media area network. Existing host bus adapters usually introduce significant latencies. Delays of as much as 10 seconds can occur between receipt of an error and the switching between ports. Such delays impose significant difficulties. Some manufacturers of host bus adapters now provide fail-over recovery software that manages port failures. Unfortunately, such software has not proven to be either transparent or seamless. Empiric testing has revealed that such software incurs latency delays as much as 15 seconds.
Thus, there is need for a technique for providing near real time recovery of faults in a MAN.